Lunar arithmetic

rdf:langString Lunar arithmetic

rdf:langString Lunar arithmetic, formerly called dismal arithmetic, is a version of arithmetic in which the addition and multiplication operations on digits are defined as the max and min operations. Thus, in lunar arithmetic, and The lunar arithmetic operations on nonnegative multidigit numbers are performed as in usual arithmetic as illustrated in the following examples. The world of lunar arithmetic is restricted to the set of nonnegative integers. 976 + 348 ---- 978 (adding digits column-wise) 976 × 348 ---- 876 (multiplying the digits of 976 by 8) 444 (multiplying the digits of 976 by 4) 333 (multiplying the digits of 976 by 3) ------ 34876 (adding digits column-wise) The concept of lunar arithmetic was proposed by David Applegate, Marc LeBrun, and Neil Sloane. In the general definition of lunar arithmetic, one considers numbers expressed in an arbitrary base and define lunar arithmetic operations as the max and min operations on the digits corresponding to the chosen base. However, for simplicity, in the following discussion it will be assumed that the numbers are represented using 10 as the base.